Clinical Outcomes after Upfront Surgery in Clinical Stage I–IIA Small Cell Lung Cancer

BACKGROUND: Upfront surgery followed by systemic treatment is recommended to treat clinical stage I–IIA small cell lung cancer (SCLC), but data on the clinical outcomes are sparse. Thus, this study evaluated the stage migration and long-term prognosis of surgically treated clinical stage I–IIA SCLC. METHODS: We retrospectively reviewed 49 patients with clinical stage I–IIA SCLC who underwent upfront surgery between 2000 and 2020. Additionally, we re-evaluated the TNM (tumor-node-metastasis) staging according to the eighth edition of the American Joint Committee on Cancer staging system for lung cancer. RESULTS: The clinical stages of SCLC were cIA in 75.5%, cIB in 18.4%, and cIIA in 6.1% of patients. A preoperative histologic diagnosis was made in 65.3% of patients. Lobectomy and systematic lymph node dissection were performed in 77.6% and 83.7% of patients, respectively. The pathological stages were pI in 67.3%, pII in 24.5%, pIII in 4.1%, and pIV in 4.1% of patients. The concordance rate between clinical and pathological stages was 44.9%, and the upstaging rate was 49.0%. The 5-year overall survival (OS) rate was 67.8%. No significant difference in OS was found between stages pI and pII. However, the OS for stages pIII/IV was significantly worse than for stages pI/II (p<0.001). CONCLUSION: In clinical stage I–IIA SCLC, approximately half of the patients were pathologically upstaged, and OS was favorable after upfront surgery, particularly in pI/II patients. The poor prognosis of pIII/IV patients indicates the necessity of intensive preoperative pathologic mediastinal staging.